KR101934359B1 - Injection mold for forming curved tube - Google Patents

Abstract

Disclosed is an injection molding mold for a curved tube having a curved pipe portion bent in a curved path. According to the present invention, the injection molding mold for a curved tube comprises: a fixed core fixed to one of an upper disk and a lower disk to have a curved protrusion through-hole; a rotation core connected to the fixed core to be able to rotate and having a curved protrusion corresponding to the inner surface shape of the curved pipe portion; a rotation-inducing block able to move close to and away from the fixed core and connected to the rotation core by a link; and a pair of curved outer surface cores able to move close to and away from each other, wherein when the pair of the cores come into close contact with each other, a curved through-hole matched to the outer surface shape of the curved pipe portion is formed. When the upper and lower disks are engaged, the pair of the curved outer surface cores come into close contact with each other in order to form cavity corresponding to the shape of the curved tube, the rotation-inducing block moves close to the fixed core, and the rotation core rotates in the direction in which the curved protrusion penetrates the curved protrusion through-hole to be inserted into the curved through-hole. When the upper and lower disks are opened, the pair of the curved outer surface cores, the rotation-inducing block, and the rotation core move opposite to the direction in which the pair of the curved outer surface cores, the rotation-inducing block, and the rotation core move when the upper and lower disks are engaged so that a curved tube molded in the shape of the cavity can be withdrawn. The present invention can increase productivity, reduce manufacturing costs, and provide a curved tube with enhanced quality.

Description

Injection mold for forming curved tube

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an injection mold, and more particularly, to a mold for injection molding a bending tube bent along a curved path and having a hollow inside.

Injection molding is a method in which a molten resin is injected into a mold and cooled to form a product. Compared with other molding methods such as compression molding and extrusion molding, And the size is limited, and productivity and workability are excellent, and it is widely used for molding of plastic products.

However, the bent tube-shaped product, which is curved along the curved path and has a hollow inside thereof, is difficult to be manufactured by the injection molding method because it is difficult to remove the inner undercut in the mold after the curing process. Thus, a method of manufacturing a bent tube by applying a heat and a pressure to form a linearly extended tube, bending the tube into a curved shape, or forming a half tube extending through a curved path, respectively, and bonding the tube to each other is applied. However, the former method is suitable for application to metal tubes, but it is not suitable for application to plastic tubes. In the latter method, the portions where the half tubes are joined to each other are not smooth and the reliability of quality is poor . Both methods have low productivity and high manufacturing cost.

Japanese Patent Application Laid-Open No. 10-1699939 discloses an injection-molding mold capable of injection-molding a flexible tube made of plastic with a curved fin interlocking with a mold opening and a mold. The injection-molding mold may include the curved fin to avoid undercuts in the side surface of the bending tube. However, an injection molding die capable of injection molding a more complicated bent tube having an undercut on the outer surface of the bending tube through one cycle of molding and molding has not been disclosed.

Korean Patent Publication No. 10-1699939

The present invention provides a bending tube injection molding die which can be injection-molded through one cycle of molding and bending cycles, in which a bending tube extending along a curved path and having an undercut on the inner side and an undercut on the outer side .

The present invention relates to a mold for injection molding a bending tube having a curved tube portion bent in a curved path, the mold comprising an upper and a lower original plate which are shaped and opened with each other, A fixed core fixed to one of the upper and lower discs and having a curved protrusion through-hole; a rotatable member rotatably coupled to the fixed core and having a curved projection corresponding to an inner shape of the curved tube portion; And a pair of cores movable in a direction in which they are in close contact with each other and in a direction opposite to the direction of rotation, And a pair of curved outer side cores formed with curved through holes corresponding to the outer shape of the curved tube portion when they are in close contact with each other, The pair of curved outer side cores are brought into close contact with each other so that a cavity corresponding to the shape of the curved tube is formed and the rotary guide block is moved in a direction approaching the fixed core, The curved projections penetrate through the curved projected through holes and are rotated in a direction to be inserted into the curved hole, and when the upper and lower circular plates are opened, the bent tubes formed in the shape of the cavity are taken out The curved outer side core, the rotation guide block, and the rotating core move in a direction opposite to a direction in which the upper and lower circular plates move together when the upper and lower circular plates are combined.

The curved tube further includes a straight tube portion extending in a straight path from one side of the curved tube portion. The curved tube injection molding die fixes and supports the rotation guide block. When the upper and lower original plates are combined A slide block moving in a direction approaching the fixed core and moving in the opposite direction when the upper and lower discs are opened; a movement block linked to the slide block, A straight outer side core having at least one portion of an inner side surface of the through hole corresponding to an outer side surface shape of the straight tube portion, and a through hole formed in the through hole of the straight outer side core Wherein at least a part of the outer surface of the inner tube is inserted into the inside of the straight tube portion Wherein when the upper disk and the lower disk are combined, the linear outer side core moves in a direction close to the pair of curved outer side cores, and the linear inner side core The straight distal end portion of the curved protrusion is moved in a direction in which the distal end of the straight distal end portion is in close contact with the distal end of the curved protrusion and the linear tube portion of the bent tube formed in the shape of the cavity is exposed, The straight inner core can move in a direction opposite to the direction in which the upper and lower circular plates move together.

Wherein the curved tube has an outer protrusion protruded from an outer surface of the straight tube portion, and when the upper and lower discs are to be opened, the straight outer core is inserted into the straight tube portion after the straight inner core exits from the straight tube portion The outer surface of the linear tube portion is exposed and the outer surface of the linear tube portion is exposed while the outer surface of the linear tube portion is exposed.

The outer surface protrusion is a ring-shaped protrusion that forms a closed curve on the outer surface of the straight tube portion. The protrusion height of the outer surface protrusion may be greater than 0 mm and less than 2 mm.

The bending tube injection molding die includes a rod fixed to the slide block and extending parallel to a moving direction of the slide block and a rod fixed to the other end of the rod and having a diameter larger than the diameter of the rod And a linear outer side core connecting pin having a head having a linear outer side core connecting pin, wherein the linear outer side core includes a pin connecting hole communicating with the linear outer side core connecting pin, A rod guide bore extending from the head guide bore to be engaged with the head guide bore having an inner diameter for receiving the head and having an inner diameter capable of receiving the rod but not receiving the head, And a stepped surface portion formed stepwise at a boundary portion between the upper plate and the lower guide plate and between the upper plate and the lower plate, The straight inner side core and the straight outer side core connecting pin move simultaneously in the same direction as the slide block and when the head is hooked on the stepped surface portion and pulls the straight outer side core, The side core can be moved in the same direction as the slide block.

An alignment protrusion is protruded from one end of the curved protrusion and one end of the linear inner core, and an alignment groove corresponding to the alignment protrusion is formed on the other end. When the upper and lower discs are formed, The alignment protrusions are inserted into the grooves so that the curved protrusions and the straight inner cores can be aligned with respect to each other.

The curved projection may extend along a circular path with the center of rotation of the rotary core as the center of the circle.

The rotary core further includes a curved protrusion support block which supports the curved protrusion and does not pass through the curved protrusion through hole. The fixed core includes a curved protrusion support block groove When the upper and lower discs are assembled together, the curved protrusion support block is caught by the peripheral portion of the curved protrusion through-hole to prevent the rotation block from being excessively rotated, and at the same time, .

The bending tube injection molding die of the present invention can be injection molded through a single molding process and a mold opening cycle in which a complicated shaped tube having an undercut due to a curved hollow on its inner surface and an undercut on the outer surface, Productivity is improved, production cost is reduced, and quality is improved.

1 is a perspective view showing an example of a curved tube.
2 is a perspective view of a bending tube injection mold according to an embodiment of the present invention.
FIGS. 3 and 4 are perspective views explaining the cores provided in the lower mold of FIG. 2, wherein FIG. 3 is a top view and FIG. 4 is a bottom view.
5 is a perspective view showing the outer circumferential surface core of the straight tube portion of Figs. 3 and 4. Fig.
FIGS. 6 to 8 are sectional views sequentially showing the movement of the cores provided in the lower mold according to the opening of the upper and lower molds of FIG. 2. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a bending tube injection molding die according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The terminology used herein is a term used to properly express the preferred embodiment of the present invention, which may vary depending on the intention of the user or operator or the custom in the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

1 is a perspective view showing an example of a curved tube. The bending tube 1 shown in Fig. 1 is injection-molded using the injection-molding metal mold 10 according to the embodiment of the present invention. 1, the curved tube 1 is a tube made of plastic and has a curved tube portion 2 bent in a curved path, a straight tube portion 3 extending in a straight path from one side of the curved tube portion 2, Respectively. The inside of the bending tube 1 is provided with a hollow hole 5 passing through the curved tube portion 2 and the straight tube portion 3. The curved tube 1 has a flange 6 radially extending at the distal end outer surface of the curved tube portion 2 and a flange 6 extending outward from the boundary portion between the curved tube portion 2 and the straight tube portion 3 A coupling stopper 7 protruding in a radial direction so as to enlarge the coupling stopper 7 so as to expand radially outwardly from the distal end surface of the straight tube portion 3, And an outer side ring-shaped projection 8. The projecting height PH of the outer side ring-like projection 8 protruding from the outer surface of the straight tube portion 3 is greater than 0 mm and less than 2 mm. In addition, the outline of the cross-section of the ring-like projection 8 is a gentle oblique slant or a curved line.

The coupling stopper 7 functions to prevent the distal end of another tube (not shown), which surrounds the outer circumferential surface of the linear tube portion 3 and is fitted to the linear tube portion 3, from entering the curved tube portion 2 side, The ring-like projection 8 is elastically brought into close contact with another tube fitted in the straight tube portion 3 to maintain a firm coupling. The flange 6 and the flange 6 of the curved tube portion 2 are connected to each other by a screw (not shown) (Not shown).

The inner surface of the bending tube 1 defined by the hollow 5 acts as an inner undercut when the bending tube 1 cured in the injection molding die is taken out of the injection molding die. The engagement flange 6 and the engagement stopper 7 and the ring-like projection 8 function as an undercut when the bending tube 1 cured in the injection molding die is taken out of the injection molding die . Therefore, a mold for injection molding the curved tube 1 requires a complicated structure for taking out the curved tube product 1 by avoiding the inner undercut and the undercut.

FIG. 2 is a perspective view of a bending tube injection molding die according to an embodiment of the present invention, FIGS. 3 and 4 are perspective views explaining the cores provided in the lower mold of FIG. 2, 4 is a bottom view, and FIG. 5 is a perspective view showing the outer periphery core of the straight tube portion of FIGS. 3 and 4. FIG. 2 to 5, the bending tube injection molding die 10 according to the embodiment of the present invention is a die for injection molding the bending tube 1 shown in Fig. 1, And is provided with an upper mold 11 and a lower mold 30 which are separated from each other in a direction parallel to the Z axis. In general, the upper mold 11 is a fixed side mold that does not move in the direction parallel to the Z axis, and the lower mold 30 becomes a movable side mold moving in a direction parallel to the Z axis. However, And the lower mold is a movable mold, the present invention is not limited thereto.

The upper mold 11 includes an upper mold base 12 and an upper circular plate 16 supported by the upper mold base 12. [ The upper mold base 12 is provided with a sprue 13 connected to a molten resin injector (not shown), and the upper circular plate 16 is connected to the sprue 13 in a fluid- And a sprue runner (not shown) extending parallel to the axis of the sprue.

The upper circular plate 16 is provided with an X-inclined pin 19 extending obliquely downward on a plane parallel to the ZX plane and a pair of Y-inclined pins 20 extending obliquely downward on a plane parallel to the YZ plane. Is fixedly supported. Further, on both sides of each of the pair of Y-warp pins 20, an upper end of a pair of Y-slide guides 23 is fixedly supported on both sides in a direction parallel to the X axis . The pair of Y-leaning pins 20 extend obliquely in directions opposite to each other, and further away from each other as they descend. A guide protrusion 24 extending obliquely in a direction parallel to the extending direction of the Y-slanted fin 20 is formed on the side surface of the Y-slide guide 23 facing the Y- The functions of the X-beveled pin 19, the pair of Y-beveled pins 20, and the pair of Y-slide guides 23 will be described later.

The lower mold 30 includes a lower mold base 31, a pair of spacers 34 supported by the lower mold base 31, a lower disc 35 supported by the spacer 34, And a fixed core (55) fixedly supported on the disk (35). When the upper mold 11 and the lower mold 30 are combined, the upper circular plate 16 and the lower circular plate 35 are formed in close contact with each other.

A circular curved protrusion through hole 56 is formed at the center of the fixed core 55. A curved protrusion supporting block receiving groove 61 is formed on the lower side of the fixed core 55, And a rotation-inducing block receiving groove 63, which is wider in a direction parallel to the Y-axis, is formed. The curved projection supporting block receiving grooves 61 and the rotation inducing block receiving grooves 63 are not separated clearly but are connected to one another. A flange-shaped groove 57 corresponding to the shape of the flange 6 of the bending tube 1 (see FIG. 1) is formed in the periphery of the curved projection through hole 56 on the fixed core 55 side.

The bending tube injection molding die 10 has three ejection openings for separating and removing the bending tube 1 formed by hardening the molten resin when the upper mold 11 and the lower mold 30 are opened from the flange- And an eject pin 33 (see Figs. 6 to 8). Three eject pin holes 59 through which the three ejection pins 33 extending upward in parallel to the Z axis are formed in the fixed core 55 are formed. The upper side openings (openings) of the three eject pin holes 59 are provided in the flange-shaped grooves 57. In the space between the pair of spacers 34, an eject plate 32 for supporting three eject pins 33 is provided. When the upper mold 11 and the lower mold 30 are opened, the ejection plate 32 is raised and the three ejection pins 33 are lifted, the upper end of the ejection pin 33 is inserted into the flange- The attached bending tube 1 is pushed up and separated from the fixed core 55. The bending tube 1 thus separated from the fixed core 55 is taken out of the injection molding die 10 by an automated robot or by an operator's manual operation.

The bending tube injection molding die 10 includes a pair of curved outer side cores 47, a pair of Y-slide blocks 41, a rotating core 70, an X-slide block 100, A link 85, a straight inner core 104, a straight outer core 90, and four straight outer core connecting pins 110. As shown in FIG. The pair of curved outer side cores 47 are movable in a direction in which the curved outer side cores 47 are in close contact with each other in parallel with the Y axis and in the opposite direction and the pair of Y- . The Y-slide block 41 and the curved outer side core 47 fixedly supported by the Y-slide block 41 are slidably supported by a Y-slide support plate 36 fixedly supported on the lower disk 35.

Each Y-slide block 41 is formed with a Y-slanted pin hole 42 extending obliquely at the same slope as the corresponding Y-slanted pin 20 so that the Y- do. A spring stopper 43 protruding inward is formed at the upper end of the inner peripheral surface of the Y-slanted pin hole 42 so that the inner diameter of the Y-slanted pin hole 42 is reduced. A damping spring 22 is fitted to the Y-beveled pin 20. The lower end of the damping spring 22 is supported by the spring stopper 43 when the lower end of the Y-slanting pin 20 is inserted into the Y-slanting pin hole 42. The upper end of the damping spring 22 And is supported by the upper disk 16.

Slide grooves 45 are formed on both sides of the Y-slide block 41 so as to extend at an inclination with the same inclination as the guide protrusions 24 so that the guide protrusions 24 are inserted. Accordingly, when the Y-slant fin 20 is fitted in the corresponding Y-slant pin hole 42 and the guide protrusion 24 is fitted in the corresponding guide groove 45, When the disk 35 is assembled, the pair of curved outer side cores 47 move in the direction in which they approach each other in parallel with the Y axis and are combined. That is, the sides facing each other are matched. At this time, the damping spring 22 is compressed to cushion the impact caused by the collision of the pair of curved outer side cores 47 and the upper circular plate 16. In contrast, when the Y-slant fin 20 is fitted in the corresponding Y-slant pin hole 42 and the guide protrusion 24 is fitted in the corresponding guide groove 45, When the disk 35 is opened, the pair of curved outer side cores 47 are moved in a direction moving away from each other in parallel with the Y-axis and opened.

The pair of curved outer side cores 47 each have a curved tube outer side surface 51 on the inner side facing each other, a runner groove 49h which is drawn out to extend parallel to the Z axis, A gate groove 50h is formed at a boundary between the groove 49h and the curved tube external shape surface 51 and a half stop groove 50h is formed on the side surface facing the straight outer core 90, (52) are formed. When a pair of curved outer side cores 47 are brought into close contact with each other, the pair of curved tube portion outer shape surfaces 51 are connected to each other to form an outer surface shape of the curved tube portion 2 (see FIG. 1) of the curved tube 1 (Not shown) corresponding to the shape of the engaging stopper 7 (see Fig. 1) of the bending tube 1 and a pair of engaging stopper half grooves 52 are formed in the engaging stopper half groove 52 (Not shown) is formed. Further, the pair of runner grooves 49h and the pair of gate grooves 50h are connected to form a runner 49 and a gate (not shown). The upper end of the runner 49 is connected to a sprue runner (not shown) of the upper disk 16.

The rotating core 70 has a curved protrusion 71 corresponding to the inner side surface shape of the curved tube portion 2 of the curved tube 1 and a portion supporting the lower end of the curved protrusion 71, A curved protrusion supporting block 74 that extends beyond the outer diameter of the curved protrusion 71 so as not to pass through the curved protrusion supporting block 74 and a pair of hinge hinges 74 which extend to both sides in the direction parallel to the Y- (77). The pair of hinges 77 are bent in the form of an alphabet letter L and the upper end portion 78 thereof is rotatably fastened to the stationary core 55 by the connecting shaft 66. In addition, three hinge supports 65 are provided on one side of the fixed core 55 facing the straight-line outer side core 90 and spaced apart from each other on a straight line in a direction parallel to the Y axis. A pair of hinge upper ends 78 are fitted in the hinge receiving grooves 66 between the adjacent pair of hinge supports 65 and the connecting shafts 66 extending parallel to the Y axis are engaged with the three hinge supports 65 The rotating core 70 is rotatably connected to the fixed core 55 in the clockwise direction and the counterclockwise direction about the connection shaft 66. As shown in FIG.

When the rotary core 70 rotates about the connection shaft 66 so that the curved projection 71 ascends, the curved projection 71 (see FIG. 6) passes through the curved projection through hole 56 of the fixed core 55 ) Protrudes upward. In this state, when the rotating core 70 is rotated in the opposite direction about the connecting shaft 66, the upper end of the curved projection 71 is flush with the curved projection through-hole 56 And the curved projection 71 is lowered so as to be positioned lower.

6 to 8, the curved protrusions 71 are formed so as to be rotatable so that the take-out of the curved tube 1 (see Fig. 1) is not hindered when the upper mold 11 and the lower mold 30 are opened, And extends along an arc path CR with the center of rotation of the core 70, that is, the connection shaft 66 as the center of the circle. Further, the curved projection 71 has a constant outer diameter or an outer diameter that becomes larger as it goes downward.

6, a stepped surface 58 is formed in the peripheral portion of the curved projection through hole 56 of the fixed core 55. The curved projection supporting block 74 of the rotating core 70 Excessive rotation of the rotating core (70) is prevented by being caught by the stepped surface (58). The curved projection supporting block 74 is inserted into the curved projection supporting block receiving groove of the fixed core 55 in a state in which the curved projection 71 protrudes through the curved projection through hole 56 as much as possible above the fixed core 55 61).

The X-slide block 100 is movably supported on the lower disk 35 in a direction parallel to the X axis. The X-slide block 100 is formed with an X-inclined pin hole 101 extending obliquely to the same inclination as the X-inclined fin 19 so that the X-inclined fin 19 penetrates. Accordingly, when the upper disk 16 and the lower disk 35 are assembled in a state where the X-slant pin 19 is fitted in the X-slant pin hole 101, the X- And moves in a direction in which it approaches the fixed core 55 in parallel. On the contrary, when the upper disk 16 and the lower disk 35 are opened in a state where the X-slant pin 19 is fitted in the X-slant pin hole 101, the X- And moves in a direction away from the stationary core 55 in parallel.

The rotation guide block 115 is fixedly supported on the X-slide block 100 and moves together as the X-slide block 115 moves parallel to the X-axis. The pair of links 85 links the pair of hinges 77 of the rotating core 70 and the rotation guide block 115. Specifically, one end of the link 77 is rotatably connected to the lower end 79 of the hinge 77 by a hinge fastening pin 88. At the other end of the link 77, a through hole 86 extending in the longitudinal direction of the link 77 is formed. The rotation guide member fastening pin 120 passes through the clearance hole 86 and is fastened to the side surface of the rotation guide block 115 so that the other end of the link 77 is rotatably connected to the rotation guide block 115 do.

The connection shaft 66 which is the rotation center of the rotary core 70 and the hinge coupling pin 88 which is the rotation center of the one end of the link 77 both extend parallel to the Y axis, Are not located at the same height in the Z-axis direction. That is, the connection shaft 66 is positioned higher than the hinge coupling pin 88. Therefore, when the X-slide block 100 and the rotation guide block 115 fixed thereto are moved toward the fixed core 55, the rotation core 70 rotates in the direction in which the curved projection 71 ascends, When the X-slide block 100 and the rotation guide block 115 fixed thereto move away from the fixed core 55, the rotation core 70 rotates in a direction in which the curved projection 71 descends.

The straight inner side core 104 is a core fixedly supported on the X-slide block 100 and extending toward the fixed core 55 in parallel with the X axis. The straight inner core 104 has a first cylindrical portion 105 having an outer surface corresponding to the inner shape of the straight tube portion 3 (see Fig. 1) of the bending tube 1, And a second cylindrical portion 108 interposed between the X-slide block 100 and the X-slide block 100 and having one side fixedly coupled to the X-slide block 100.

The end face of the first cylindrical portion 105 is brought into close contact with the end face of the curved projection 71 when the upper circular plate 16 and the lower circular plate 35 are engaged. Alignment protrusions 106 protrude from end surfaces of the first cylindrical portion 105 and alignment grooves 72 corresponding to the alignment protrusions 106 are formed on end surfaces of the curved protrusions 71. When the upper disk 16 and the lower disk 35 are engaged with each other, the alignment protrusions 106 are inserted into the alignment grooves 72 and the curved protrusions 71 and the straight inner cores 104 are engaged with each other . 3 and 4, an alignment protrusion may protrude from the curved protrusion 71, and an alignment groove may be formed in the straight inner core 104. As shown in FIG.

The linear outer-side core 90 is a core that moves in association with the X-slide block 100. The linear outer-side core 90 is a core that extends parallel to the moving direction of the X-slide block 100, (91) is formed. The inner circumferential surface of the X-through hole 91 has a straight tubular shape corresponding surface (not shown) corresponding to the outer shape of the straight tube portion 3 (see FIG. 1) of the bending tube 1 on one side relatively close to the fixed core 55 And a straight inner core-type mating face 94 provided on the other side relatively far from the fixed core 55. [ When the upper mold 11 and the lower mold 30 are combined, the straight inner core type mating face 94 and the outer peripheral face of the rectilinear inner core second cylindrical portion 108 are fitted to each other without tight contact. A ring-like projection-like shape corresponding to the shape of the outer side ring-shaped projection 8 (see FIG. 1) of the bending tube 1 is formed at the distal end portion of the straight tubular portion- A surface 93 is provided.

The ring-like projection-like surface 93 is formed so that its depth PH (see Fig. 6) is greater than 0 mm and within 2 mm in correspondence with the height PH of the ring-shaped projection 8 (see Fig. 1) Is a slant or curved line with a gentle slope. When the height PH of the ring-shaped projection 8 is 0 mm, it can not be a projection. On the other hand, if the height PH is larger than 2 mm, it may be difficult to take out the bending tube 1 (see FIG. 1) from the mold 10 by using the elastic restoring force of the straight tube portion 3 (see FIG. 1) Even if the bending tube 1 can be taken out from the mold 10, a permanent deformation that is not resiliently restored to the bending tube 1 can be left.

Each of the four linear outer-side core connection pins 110 is a pin extended in the moving direction of the X-slide block 100, that is, in a direction parallel to the X-axis, And a head 111 fixed to the other end of the rod 112 and having a diameter larger than the diameter of the rod 112. The rod 112 is fixed to the rod 112 and extends parallel to the X- do. The head 111 and the rod 112 may be fixedly coupled or integrally produced. Four straight outer-side core connection pins 110 are disposed in the periphery of the straight-line inner core 104.

Four straight pinned through holes 95 are formed in the linear outer side core 90 so as to extend in parallel with the X axis and into which the four linear outer side core connecting pins 110 are inserted. Four pin coupling holes 95 are formed in the periphery of the X-hole 91. Each of the pin coupling holes 95 has an inner diameter sized to accommodate the head 111 so that it has an inner diameter that accommodates the rod 112 but does not accommodate the head 111, An excited rod guide passage 97 and a stepped surface portion 98 formed stepwise at a boundary portion between the head guide passage 96 and the rod guide passage 97.

FIGS. 6 to 8 are sectional views sequentially showing the movement of the cores provided in the lower mold according to the opening of the upper and lower molds of FIG. 2. FIG. Hereinafter, the opening operation of the bending tube injection molding die 10 will be described with reference to these drawings sequentially. 2 to 6, the curved through-hole and the engaging stopper-shaped groove formed by closely contacting a pair of curved outer side cores 47 when the upper circular plate 16 and the lower circular plate 35 are formed, The flange-shaped groove 57 of the fixed core 55, the outer circumferential surface of the curved projection 71 of the rotating core 70, the straight tubular portion corresponding surface 92 of the straight outer side core 90 and the ring- A cavity is defined by the surface 93 and the outer circumferential surface of the first cylindrical portion 105 of the straight inner core 104.

At this time, the inclined surface 117 formed on the rotation inducing block 110 is tightly contacted with the inclined surface 81 formed on the lower side of the curved projection supporting block 74 of the rotating core 70. The end face of the straight inner core 104 and the end face of the rotation protrusion 71 are in close contact with each other and the alignment protrusion 106 is inserted and seated in the alignment groove 72. The outer peripheral surface of the second cylindrical portion 108 of the linear inner side core 104 and the linear inner side core-shaped mating surface 94 of the linear outer side core 90 are also in close contact with each other.

When the molten resin is injected into the mold 10 through the sprue 13, the molten resin is injected into the cavity through the sprue runner (not shown), the runner 49 and the gate, The molten resin injected into the cavity is formed into the bending tube 1 by the cooling hardening. At this time, the molten resin cooled and cured in the state of being injected into the runner 49 and the gate is formed into a waste 9. The waste 9 is removed from the bending tube 1 after the bending tube 1 is taken out from the mold 10.

2 to 5 and FIG. 7 together, when the upper disk 16 and the lower disk 35 start to be opened, the pair of curved outer side cores 47 are spaced from each other in a direction parallel to the Y axis And the outer surface of the curved tube portion 2 of the curved tube 1 starts to be exposed. The X-slide block 100 and the four linear outer side core connection pins 110, the rotation guide block 115 and the linear inner side core 104 fixedly coupled to the X-slide block 100 are spaced apart from the fixed core 55 Simultaneously, it moves in a direction parallel to the direction of positive X-axis.

The linear inner side core 104 is withdrawn from the straight tube portion 3 of the bending tube 1 and the rotating core 70 pulled by the link 85 rotates about the connecting shaft 66, The projection 71 starts to come out from the curved tube portion 2 of the curved tube 1. [ The head 111 moves in the head guide passage 96 of the pin fixing hole 95 even if the four linear outer side core connection pins 110 move in the direction away from the stationary core 55, The straight outer-side core 90 does not move in synchronization with the X-slide block 100 until the stepped surface 111 reaches the stepped surface portion 98.

2 to 5 and 8, when the upper disk 16 and the lower disk 35 are completely separated from each other, the pair of curved outer side cores 47 are further separated from each other in the Y axis So that the outer surface of the curved tube portion 2 of the curved tube 1 is entirely exposed. The X-slide block 100 and the four linear outer side core connection pins 110, the rotation guide block 115 and the linear inner side core 104 fixedly coupled to the X- And simultaneously moves in a direction parallel to the positive X-axis direction.

The straight inner core 104 is further spaced from the straight tube portion 3 of the curved tube 1 and the rotating core 70 pulled by the link 85 is further rotated about the connecting shaft 66 The curved protrusion 71 completely protrudes from the curved tube portion 2 of the curved tube 1 so that the end surface of the curved protrusion 71 is positioned at the same height as the entrance of the curved protrusion through hole 56 or at a height slightly lower .

The head 111 is caught by the stepped surface portion 98 of the pin securing through hole 95 so that the straight outer side core connecting pin 110 is engaged with the straight outer side core connecting pin 110, The straight outer side core 90 is moved in the same direction as that of the X-slide core 100 since the outer side core 90 is pulled by the four straight outer side core connecting pins 110. In other words, when the upper disk 16 and the lower disk 35 are opened, the straight outer core 90 is inserted into the linear tube portion (not shown) after the straight inner core 104 exits the straight tube portion 3 3 are exposed in the exposed direction.

The outer side ring-shaped projection 8 of the bending tube 1 has an element which interferes with the movement of the linear outer side core 90 parallel to the positive X-axis direction, that is, an undercut ). ≪ / RTI > However, since the bending tube 1 is a plastic product which can be elastically deformed to a certain extent and since the straight inner core 104 has already passed through the inside of the straight tube portion 3 and the straight tube portion 3 can be rolled, The outer side ring-shaped protrusion 8 is formed on the straight tubular shape corresponding surface 92 of the straight outer side core 90 when the straight outer side core 90 moves in the direction in which the outer side surface of the straight tube portion 3 is exposed. So that the straight outer-side core 90 can escape from the outer surface of the straight tube portion 3. As shown in Fig. The straight tube portion 3 is resiliently restored to its original shape after the straight outer core 90 is completely separated from the outer surface of the straight tube portion 3 and exited. When the three eject pins 33 rise in the state of FIG. 8, the bending tube 1 is separated from the flange-shaped groove 57 of the fixed core 55 and can be taken out.

On the other hand, the process of forming the upper disk 16 and the lower disk 35 from the opened state proceeds in the reverse order of the above-described opening process. That is, when the upper disk 16 and the lower disk 35 are combined, a pair of curved outer side cores 47 are formed so as to form a cavity corresponding to the shape of the bending tube 1, The X-slide block 100 and the rotation guide block 115 fixedly coupled to the X-slide block 100 move in a direction approaching the fixed core 55 in parallel with the X axis, The curved protrusions 71 penetrate the curved protrusion through holes 56 and the pair of curved outer side cores 47 come into close contact with each other to form curved through holes 56, As shown in FIG.

The linear inner side core 104 moves in the same direction with the X-slide block 100 so that the end face of the first cylindrical portion 105 is in close contact with the end face of the curved projection 71. The straight outer-side core 90 moves in a direction to come close to the pair of curved outer-side cores 47 so as to be delayed from the straight inner-side core 104. The head 111 of the four linear outer side core connection pins 110 is spaced apart from the stepped surface portion 98 of the four pin engagement through holes 95 and moves along the head guide passage 96, The outer side core 90 does not move but the linear outer side core 90 contacts the linear outer side core 90 while the X-slide block 100 presses in the same direction as the X-slide block 100 And is brought into close contact with the pair of curved outer side cores 47.

The bending tube injection molding die 10 described above has a complicated shape of the bending tube 1 in which not only the undercut due to the curved hollow is present on the inner side but also the undercut exists on the outer side, Injection molding can be performed, productivity of work is improved, production cost is reduced, and quality is improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

1: Flexure tube 10: Flexure tube Injection molding die
19, 20: oblique pin 30: lower mold
41: Y-slide block 47: Curved outer side core
55: stationary core 70: rotating core
90: straight outer core 104: straight inner core
100: X-slide block 115: rotation induction block

Claims (8)

delete A mold for injection molding a bending tube having a curved tube portion bent in a curved path,
An upper and a lower original plate which are formed and opened to each other; A fixed core fixed to one of the upper and lower discs and having a curved protrusion through-hole; A rotating core rotatably coupled to the stationary core and having a curved projection corresponding to an inner shape of the curved tube portion; A rotation induction block movable in a direction approaching and away from the fixed core and connected to the rotation core by a link; And a pair of curved outer cores formed in a pair of cores movable in a direction in which they are in close contact with each other and in a direction opposite thereto and in which curved through holes corresponding to the outer shape of the curved tube portion are formed when they are in close contact with each other,
The pair of curved outer side cores are brought into close contact with each other so that a cavity corresponding to the shape of the curved tube is formed when the upper and lower main plates are combined, And the rotating core rotates in a direction in which the curved projections penetrate the curved projection through holes and are inserted into the curved hole,
When the upper and lower circular plates are formed, the pair of curved outer side cores, the rotation induction block, and the rotating core are combined to form the upper and lower circular plates so that the curved tube formed in the shape of the cavity is taken out When you move in the direction opposite to the direction of movement,
Wherein the curved tube further comprises a straight tube portion extending in a straight path at one side of the curved tube portion,
The curved tube injection molding die fixes and supports the rotation guide block. When the upper and lower circular plates are combined, the curved tube injection molding die moves in a direction toward the fixed core. When the upper and lower circular plates are formed, A slide block that moves to a second position; Wherein a through hole extending parallel to the moving direction of the slide block is formed by moving in conjunction with the slide block, and at least a portion of the inner side surface of the through hole corresponds to an outer side surface shape of the straight tube portion ; And a linear inner side core fixedly supported on the slide block and extending in a direction to be inserted into a through hole of the linear outer side core, wherein at least a portion of the outer side of the straight side inner core corresponds to an inner side shape of the straight tube portion; Respectively,
When the upper disk and the lower disk cooperate, the straight outer core moves in a direction close to the pair of curved outer cores, and the straight inner core has its end closely contacted with the end of the curved projection Direction,
The linear outer side core and the linear inner core move when the upper and lower circular plates are engaged with each other so that the straight tube portion of the bent tube formed in the shape of the cavity is exposed, Wherein the mold is moved in a direction opposite to the direction of the injection molding. 3. The method of claim 2,
Wherein the bending tube has an outer surface projection projecting from an outer surface of the straight tube portion,
The straight outer core moves in a direction in which the outer side surface of the straight tube portion is exposed after the straight inner core portion comes out from the straight tube portion,
Wherein the outer side surface core is elastically deformed by being pressed by the outer side surface core while moving in a direction in which the outer side surface of the straight tube portion is exposed. The method of claim 3,
Wherein the outer surface protrusion is a ring-shaped protrusion forming a closed curve on the outer surface of the straight tube portion, and the protrusion height of the outer surface protrusion is greater than 0 mm and within 2 mm. The method of claim 3,
The bending tube injection molding die includes a rod fixed to the slide block and extending parallel to a moving direction of the slide block and a rod fixed to the other end of the rod and having a diameter larger than the diameter of the rod And a straight outer-side core connecting pin having a head having a head,
Wherein the linear outer side core is formed with a pin fixing hole through which the linear outer side core connecting pin is inserted,
The pin-tightening hole has a rod-guiding cylinder head which is engaged with the head-guiding cylinder so as to have an inner diameter for receiving the head, which is engaged with the head-guiding cylinder and has an inner diameter accommodating the rod but not receiving the head, And a stepped surface portion formed stepwise at a boundary portion between the head guide cylinder portion and the rod guide cylinder portion,
The straight inner core and the straight outer core connecting pin are simultaneously moved in the same direction with the slide block, and the head is hooked on the stepped surface portion, Wherein the straight outer-side core moves in the same direction as the slide block from the time of pulling. 3. The method of claim 2,
An alignment protrusion is protruded from one end of the curved protrusion and one end of the straight inner core, and an alignment groove corresponding to the alignment protrusion is formed on the other end,
Wherein when the upper disk and the lower disk are combined, the alignment protrusions are inserted and seated in the alignment grooves, so that the curved projections and the straight inner cores are aligned with respect to each other. 3. The method of claim 2,
Wherein the curved projection extends along a circular path having the center of rotation of the rotary core as a center of the circle. 3. The method of claim 2,
The rotating core further comprises a curved protrusion supporting block which supports the curved protrusion and does not pass through the curved protrusion through hole,
Wherein the fixed core has a curved projection supporting block receiving groove formed therein for receiving the curved projection supporting block,
Wherein the curved projection supporting block is engaged with a peripheral portion of the curved projection through hole to prevent excessive rotation of the rotary core and is received in the curved projection supporting block receiving groove when the upper and lower original plates are combined. Tube injection molding mold.

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